Arc-lamp.



R. HEWSON.

ARC LAMP.

APPLICATION FILED JUNE 5, 190a.

Patented Feb. 22, 1910.

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A T T3? R. HEWSON.

ABC LAMP,

APPLICATION FILED JUNE 5, 1908.

Patented Feb. 22, 1910.

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UNITED STATES PATENT OFFICE.

ROBERT HEWSON, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION 01? NEW YORK.

ARC-LAMP.

Specification of Letters Patent.

To all whom it may concern:

Be it known that I, ROBERT HnwsoN, a citlzen of the Domlnlon of Canada,residing at Lynn, county of Essex, State of Massachusetts, have inventedcertain new and useful Improvements in Arc-Lamps, of which the followingis a specification.

My invention has reference to improve ments in arc lamps of the kind inwhich for the establishment of the arc and also at intervals during thefeeding operation the two electrodes are forcibly brought together andare then separated by gravity to the arcing distance. In these lamps areordinarily employed cathodes, which, in consuming, yield the gases orvapors which maintain the arc, while the anode is, as a rule, althoughnot always, of a piece of metal of good conductivity of heat andelectricity which, theoretically speaking, is not at all consumed, butwhich has proved in practice to become consumed at a slow rate wherebyits arcing end becomes irregularly disfigured. terial which becomesfused at the arcing end, formingthere a. little pool from which the arcsprings. In these lamps the inconvenience has been experienced that whenthe cathode, which is usually the lower electrode, is forcibly broughtinto contact with the anode, the two electrodes become wedged together,due sometimes to the irregularities of their end surfaces and sometimesto looseness of their mountings or guides, so that they become displacedlaterally with reference to each other, and thus wedge together. If thishappens the cathode, which in such lamps is arranged to separate fromanode by gravity merely, is held locked to the same by the wedgingaction and cannot separate and the are cannot be formed, and the undulygreat amount of current which is thus allowed to pass through the lampis liable to injure the parts. Sometimes it also happens that the anodefreezes to the cathode pool superficially, and the establishment of theare may be prevented for this reason also.

My invention is designed to overcome these difiiculties, and it consistsin a weight bearing upon the cathode carrier, or to any part moving withthe cathode, in such manner that when the cathode is forcibly thrownupward toward the anode, the weight will.

move with it, and will by its inertia move The cathode is usually madeof a ma- 0 farther than the cathode itself, which is arrested by contactwith the anode. This weight, dropping down to its original position,will act as a driver upon the cathode carrier, and forcibly separate theelectrodes even if they have been rather tightly wedged or have frozentogether. All this will more fully appear from the following detaileddescription with reference to the accompanying drawing, in which Figure1 represents an elevation of the operating mechanism of an electric arclamp of the kind to which my invention applies, with its circuitconnections, the electrodes being shown separated; and Fig. 2 represents the same lamp mechanism in the condition when the electrodes havejustcome into contact, the circuit connections being omitted.

Like numerals of reference indicate like parts throughout the drawing.

In the drawing 1 and 2 represent respectively a positive and a negativeelectrode of a luminous arc lamp. The positive electrode is shown in theform of a non-consuming copper rod having wing-like extensions 3 and 4,which pass through slots 5 in the walls of the fume-box 6. In theseslots the wings of the electrode may be held in a fixed position, but,as here shown, the wings rest upon pins 7 projecting into the slots andthus normally support the wings a short distance below the upper ends ofthe slots, so

that the electrode 1 may rise a short distance by the impact of theelectrode 2 and is then free to fall down this short distance when theelectrode 2 drops away. A platform 8 supports the fume-box and from theupper side of the platform extends the chimney 9, it being understoodthat the platform has a wide opening registering with the upper end ofthe fume-box 6 and with the lower end of the chimney. In the drawing thechimney is shown as broken off. The negative electrode 2 is shown assupported and operated in a wellknown manner. A tube 10 passesvertically through the platform and through a guide tube 10 and carriesat its lower end an arm 11 which terminates in a socket 12 in which thenegative electrode is clamped. The tube 10 is guided at its upper end bymeans of a rod 13 which projects downward from a bracket 14 supported bya standard 15 which is mounted on a secondary platform 16 insulated fromthe main Patented Feb. 22, 1910.

platform 8. 17 and 18 are the lifting and holding clutches, of any usualconstruction. The function of the lifting clutch is to engage thesupporting tube of the lower electrode and move it vertically until thiselectrode has come into forcible engagementwith the upper electrode. Thefunction of the holding clutch is to cooperate with the support for thelower electrode so as to permit this electrode to drop a predetermineddistance away from the upper electrode after the two electrodes havebeen brought into engagement by means of the lifting clutch. The liftingclutch is operated by a suitable regulating magnet having an armature 19and an energizing coil 20, and this magnet is in turn controlled, so asto become energized after the two electrodes have come into engagement,and thus permit the separation of the electrodes for the establishmentof the arc. The core of the eleciromagnet has attached to its yoke astem 21 provided with a shoulder or collar 22, upon which the end of thepawl arm 23 of the lifting clutch 1T rests. ll' llGH the magnet isenergized, the core is drawn upward, the lifting clutch is brought intooperative engagement with the tubular portion of the carrier of thelower electrode and is then carried vertically upward until the lowerelectrode is brought into engagement with the upper electrode. Theholding clutch 18 is illustrated as being of the usual floating tyne.normally locked to the tubular support of the lower electrode by meansof the elongated spring Eat, the upper end of which is hooked to aportion of the bracket 14 and the lower end to the pawl 25 of the clutch18. Normally, this clutch rests upon the fixed stop 26, rising from theauxiliary platform 16. \V hen the lifting movement begins, the holdingclutch travels with the electrode carrying tube 10 until it comes intoengagement with a second fixed stop 27, which is arranged at somedistance above the stop 26. The stop 27 arrests the movement of theholding clutch, which, how ever, permits the electrode supporting tubeto continue its upward movement, since by the engagement of this clutchwith the stop 27 the clutch releases the tube 10. lVhen theelectromagnet is deenergized, the lower electrode and its supportingtube begin to drop, butthe holding clutch immediately again grips thetube 10 and is carried downward with it until it again strikes the stopAt this time both the clutch and electrode are brought to rest. Adashpot controls the speed of descent of the lower electrode; themovable member 28 of this dashpot being connected to the stem 21, whilethe stationary member 29 is fixed to the platform 8.

In Fig. 1 the parts are shown in the normal running position, which isalso the position when the current is turned 05 from the lamp. Inaddition to the main regulating magnet there are two auxiliary magnets30 and 31, the first having a coil which is in series with theelectrodes and the other a coil which is in series with the coil of themain magnet. To the respective cores of the auxiliary magnets areattached contacts 32 and 33, which, when they engage, place a shuntabout the coil of the electromagnet 31 and connect the coil of the mainmagnet across the line in series with a resistance When both magnets 30and 31 are deenergized, the contacts and 33 engage, while during thesubstantial deenergization of magnet 81 and the energization of magnet30 the contacts are out of engagement. llhen current is thrown on, thecontacts 32 and being in engagement, a circuit is established throughthe main electromagnet, while the electromagnet 31 remains deenergized.The lower electrode 2 is therefore aised in the manner described, untilit engages with the upper electrode. Current now flows from theelectrodes in series with the coil to electromagnet 30, and this magnet,being energized, lifts the contact out of engagement with contact 33,thereby connecting the coil of magnet 31 in series with the coil of themain magnet. The current through the main magnet is now so diminishedthat its armature drops, freeing the tube 10, which now also drops,carrying with it the lower electrode. As the arc lengthens, magnet 30becomes weaker and magnet 31 stronger, until a point is reached when thecontacts 32 and are brought together; whereupon the main magnet is againoperatively energized and the lower electrode is lifted as before.

The lamp so far described is essentially the same as that shown in anapplication filed by Richard Fleming on December 28, 1905, Serial No.293,590, or the one shown in an application filed by Cromwell A. ll.llalvorson, J r. on March 7, 1907, Serial No. 361,051; and l have heredescribed this lamp only as exemplifying the character of lamp to whichmy invention applies, namely; as one in which one of the electrodes isbrought into forcible contact with the upper electrode and is thenallowed to drop away from the same for the establishment of the arc. Ashas heretofore been pointed out, in such lamps the electrodes sometimeswedge together or freeze together, and my invention is designed toinsure the establishment of the are if such wedging or freezing occurs.For this purpose I use a weight 35, which rests upon the lower electrodecarrier, and in the case here particularly shown it rests upon the arm11, being for this purpose shaped like the link of a chain, as isclearly shown, the opening of the link being wide enough to slip overthe boss 36 which is sometimes made in one piece with the arm 11, and towhich the electrode l l i) 2, and when the contact is made, the lowerelectrode is suddenly arrested; but the weight 35, which by that timehas attained a considerable momentum, continues to rise upwardly and mayrise, as shown in Fig. 2, throughout the whole length of the loop orlink openin At that moment the electrode carrying tube 10 is releasedfrom the clutch l7 and has now tendency to drop down so as to establishthe are between the electrodes. If it should happen, as it frequentlydoes, that the electrodes are wedged together or are frozen together,the weight will nevertheless fall down from the position shown in Fig. 2to the position shown in Fig. 1, and will strike the lower electrodecarrier a heavy blow that will free the lower electrode from the upperand will allow it to descend by gravity for the establishment of thearc. The weight 35 may take any desirable shape and may be mounted onany part of the structure that moves with the lower electrode. Theweight should be made heavy enough to surely free the lower electrodefrom the upper, but it need not be made heavier than this.

The invention is applicable to all kinds of arc lamps in which the arcis established by two movements of at least one of the electrodes, viz.a contacting and a separating movement, irrespective of the character ofthe electrodes.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. In an arc lamp, a means for separating the wedged or frozenelectrodes, consisting of a free weight impacting one of the electrodecarriers in the direction of its arcstrilring movement.

2. In an arc lamp, the combination of an arc-striking electrode havingtwo opposite movements, with a weight thrown by one of the movements andstarting by its fall the reverse movement.

In an arc lamp, the combination of a stationary and of an arc-strikingelectrode having two movements, with a free weight thrown upward by onemovement of the electrode and aiding by its fall the other movement.

4:. In an arc lamp, in which one electrode is positively moved incontact with the other stationary electrode and is then released forgravitational arcstriking movement, a free weight moved upwardly by thecontact movement of the electrode and released to assist by its weightthe arc-striking movement.

5. In an arc lamp, the combination of a stationary electrode and amovable electrode, the latter being positively actuated to contact withthe former and then released for gravitational arc-striking movement,with a free weight adapted to be thrown upward by and beyond the contactmovement and which by its descent starts the arc-striking movement.

6. In an arc lamp, the combination of a stationary electrode, a movableelectrode, means for positively actuating the latter to move in contactwith the stationary electrode, means for releasing the movable electrodefrom the actuating mechanism for gravitational arc-striking movement,and a weight arranged to reinforce the gravitational movement.

7. In an arc lamp, the combination of two electrodes in verticalalinement, means for lifting the lower electrode into engagement withthe upper electrode and then releasing it from the lifting mechanism,and a weight resting upon the lower electrode carrier and guided forfree vertical movement above the same.

In witness whereof, I have hereunto set my hand this 27th day of May,1908.

ROBERT I-IEWVSON.

IVitnesses BENJAMIN F. REAGIN, IVALTER L. BALLARD.

